The cause of Parkinson's disease (PD) remains elusive but almost certainly involves genetic and environment factors. A number of potential risk factor genes and environmental toxins (especially pesticides) have been implicated but it is still not known if these factors actually cause PD. Current animal models to test causality of these factors and interactions between the two are inadequate. We propose to use zebrafish to test potential genetic and environmental causes of PD because they have several advantages over current animal models. Zebrafish are vertebrates, small, have a short life cycle, are relatively easy to insert transgenes, and the larvae are transparent enabling imaging of molecular and cellular processes in living animals. Behavior can also be readily measured. We propose to take advantage of these unique characteristics to determine the potential etiological roles of PD risk factor genes and environmental toxins implicated in PD and interactions between genes and the environment. We hypothesize that some toxins will alter locomotor and olfactory behavior and induce selective dopaminergic cell death and pathology similar to that seen in PD. It is also possible that the toxicity of some genes and toxins will only be apparent in combination (gene-environment interaction). Specifically, we will characterize the behavioral effects resulting from lesions in specific dopaminergic cell clusters made with a 2-photon laser and identified using a zebrafish tyrosine hydroxylase promoter driving green fluorescent protein (zTH-GFP). We will then be able to use behavioral measurements to screen for effects of PD genes and toxins on the dopaminergic system. PD- associated genes to be tested include alpha-synuclein and LRRK2. Toxins to be tested will include the ubiquitin-proteasome system (UPS) inhibitor epoxomicin, and pesticides identified to be inhibitors of the UPS using a high throughput screen performed in a neuroblastoma cell line. Expression of the zTH-GFP transgene will also facilitate pathological evaluation of toxin-exposed zebrafish and fish expressing PD genes. These studies will not only provide valuable information on the contributions PD genes and environmental toxins make to the pathogenesis of PD, but also will create a powerful model to test potential disease modifying therapies. PUBLIC HEALTH RELEVANCE: Parkinson's disease (PD) affects approximately 1 million Americans but the cause remains elusive. We propose to investigate genetic and environmental contributions to the development of PD using a novel zebrafish model. The results of these experiments will provide valuable information into the cause of PD and move us closer to the development of meaningful disease modifying therapies.